I just upgraded the stock Firestone 265/75/16's to BFG 285/75/16's. I have a 2000 F-250, 5.4, 5 sp, 4x4. Everything seems to be working just fine, mileage and speedo seems a bit off, but not by much, ABS works fine. Should I mess with the dealer recalibrating my computer for $70? Or is not worth messing with?

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-IKE

2000 F-250 SuperDuty Crew Cab 4x4

"My graduation present to myself!"

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1999 Graduate -Purdue University
"Close by the Wabash, in famed Hoosier land..."
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Ike,

If the tire specs you posted are correct, you've only increased your tires width, not the height. To my knowledge, this would be no reason to mess with your speedo at all.

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1999 Lariat 4X4 SuperCab Flareside 5.4; Auto, Tow Pack, Offroad Pack, 3.73LS, Factory Step Bars, 17" Chrome Wheels, Oxford White/Silver, Graphite Leather, Keypad Mod., Airaid, SuperChip, ARE LSII Bed Cover, Alpine CDA-855/JBL AMP, Polk dX7's, Custom cat-back exhaust.

 

The specs are correct, although the "75" in both cases is the aspect ratio, which is the height of the sidewall in relation to width, so they are in fact 2 different sized (diameter) tires since they have differing widths.

-IKE

 

while I am no expert on this, I believe the change in tire diameter can have an adverse affect on the transmission down the road. I believe all that's needed is a change of the little speedo gear in the transmission.

what I want to know is, how did you get a 5 speed tranny with a 5.4? I thought the 5.4 only came with auto tranny!

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[This message has been edited by Jim Mc (edited 10-28-2000).]

 

Unless every posting on this board is wrong, a 2000 does not have a speedo gear in the tranny, requiring a trip to the dealer for reprogramming of the PCM. I went to a local Ford dealer and the service writer got that "deer in the headlights" look when I told them what I needed. So, I didn't have it done yet (ever?)

As for the 5.4 and 5 sp, it is standard equipment on the SuperDuty, but I did have to order the truck to get that combo with a crew cab. All I could find on the lots were PSD or V-10 crew cabs and the few with 5.4's had the auto.

-IKE

 

A: Not if you're leasing by the miles.

 

Not leasing (good point, though!!! ) It's owned outright. From what I've determined the speedo's off about 4%, which I'm assuming in this case means that I'm showing only 96 miles on the odometer for every 100 actual miles (or something like that.) If I'm wrong please let me know!

-IKE

 

Ike,

I stand corrected. I didn't realize it was a ratio of tire size, so obviously a wider tire will have a taller stance. There must information somewhere that you could plug in your before and after tire sizes and get an idea of how many mph your speedo would be off. Just an idea before you drop coin at the dealer.

 

I recall seeing something on this board a while back about recalibrating the speedo to compensate for gears, tires, etc. It has something to do with starting the vehicle in diagnostic mode (switching the ignition of and on a specified number of times). Once in this mode, you can adjust the speedo yourself from the drivers seat.

Try to do a search on speedo recalibrations. I'm positive it's here somewhere. No sense paying the dealer to do something you can do yourself in a matter of a few minutes. But, if my memory's right, you can only reprogram the speedo 6 times (?)...


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VENOM 99
2000 F-150 SuperCab 4x4
Off-Road package
Extang BlackMax tonneau cover
BedRug
www.students.uiuc.edu/~cellariu

 

VENOM 99: I did search for that info. initially, and I did read the post you mentioned, but I think you can only do that with a digital odometer(?) which I don't have. That's what I got out of the post, if there is in fact a way for me to do it, please let me know..

Thanks!
-IKE

 

Sorry IKE, I didn't realize the 250s didn't have the digital odometer like us little 1/2 boys have...

In that case, I don't know if there's any other way to recalibrate other than to contact the dealer.

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VENOM 99
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